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Factors affecting the rate of reation

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Hi Guys,

I really need you help, I have to give in a lab report day after tomorrow. It is about the rate of reaction and the factors which affect the reaction. I did it at the beginning of the year and can't remember a thing from it. All I have are results, which are HCL concentrations over time, Does anyone have any idea how this could have been carried out? Thanks for your help in advance.

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Well, it's difficult to pinpoint exactly how you carried it out, as you haven't given any other information but here's something which might jog your memory (or not, I don't know. Hope it's helpful to some extent though.)It's the method for an experiment:

The Effect of Changes in Molar Concentration

1. Using a clean dry graduated cylinder, measure 20.0 mL of 1.0 M HCl. The temperature of the HCl solution should be 20°C. Pour it carefully into the

flask.

2. Using a piece of folded filter paper, a clean plastic spoon, and a centigram balance,

obtain 1.00 g of baking soda (NaHCO3).

3. If you have a pneumatic trough, place a test tube or graduated cylinder full of water over the tubing. If you are using a large pan of water, have your partner hold

the tube or cylinder in place over the tubing. Make sure the tubing remains under

water at all times.

4. Remove the stopper from the flask and add the baking soda to the HCl.

5. Quickly replace the stopper and start the stopwatch.

6. Stop the stopwatch when all the water has been displaced from the inverted tube.

Record the elapsed time in your data table.

7. Dispose the contents of the flask in the sink and flush with plenty of water. Rinse

the flask and reassemble the gas collection apparatus.

8. Using a clean graduated cylinder, measure 5.0 mL of water and add it to the flask. Measure out and add 15.0 mL of 1.0 M HCl to the flask.

9. Repeat Steps 2-7.

10.Do two more trials, one using 10 mL or water and 10 mL of HCl and the other using 15 mL of water and 5 mL of HCl.

Anyway, good luck with it. The molar concentrations you would've used, are most probably different but perhaps the method's the same. I really don't know. You shouldn't have left it till now though...:)

Edited by nαmetαken

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I'm going to guess you did changes in your concentration as your independent variable. Temperature you probably would've wrote down. You can't do pressure with a liquid (in a high school at least...). And a catalyst would just result in only 2 trials really, 1 with and 1 without.

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Hi Guys,

I really need you help, I have to give in a lab report day after tomorrow. It is about the rate of reaction and the factors which affect the reaction. I did it at the beginning of the year and can't remember a thing from it. All I have are results, which are HCL concentrations over time, Does anyone have any idea how this could have been carried out? Thanks for your help in advance.

Mass loss over time? Gas produced over time? Time taken for colour change/complete reaction?

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Hi Guys,

I really need you help, I have to give in a lab report day after tomorrow. It is about the rate of reaction and the factors which affect the reaction. I did it at the beginning of the year and can't remember a thing from it. All I have are results, which are HCL concentrations over time, Does anyone have any idea how this could have been carried out? Thanks for your help in advance.

Mass loss over time? Gas produced over time? Time taken for colour change/complete reaction?

He already has results, just doesn't know what he did to get them XD

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Hi Guys,

I really need you help, I have to give in a lab report day after tomorrow. It is about the rate of reaction and the factors which affect the reaction. I did it at the beginning of the year and can't remember a thing from it. All I have are results, which are HCL concentrations over time, Does anyone have any idea how this could have been carried out? Thanks for your help in advance.

Mass loss over time? Gas produced over time? Time taken for colour change/complete reaction?

He already has results, just doesn't know what he did to get them XD

Precisely. All she has is some results for her independent variable which was concentration of HCl, so what is the dependent variable? It could be as you said temperature change, but it also could be showing mass loss, the volume of gas produced, the time taken for colour change/complete reaction ect.

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I see, didn't read it like that the first time sorry. Also, how does color change lead to concentration changes? O.o

Time taken for colour change is not a independent variable, it is a dependent.

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Yea, I meant how do you take the measured color changing time thingy and get concentration from it? How do you process that? O.o

I'm slightly confused. You accept that HCl concentration is the independent variable yet you are questioning how you get HCl concentration from the time taken for a colour change. That is not how an independent variable works. Independent variable: Concentration of HCl 0.2M, 0.4, 0.6, 0.8 ect. Dependent variable: time taken for colour change. Rate of reaction for each independent variable = 1/time taken for colour change.

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Her RESULTS (dependent variable) are the concentrations over time graphs she already has O.o I was trying to relate your color changing dependent variable post to how she could possible get her graphs O.o

I think we've done confused each other...

And I know how variables work >.>

Edited by Drake Glau

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I'm going to guess you did changes in your concentration as your independent variable. Temperature you probably would've wrote down. You can't do pressure with a liquid (in a high school at least...). And a catalyst would just result in only 2 trials really, 1 with and 1 without.

Could you explain your first sentence? And what experiment would give a HCl concentration over time reading? I cannot think of any. Changing the concentration of HCl is nearly always an independent variable in rate of reaction experiments, I cannot think of a scenario where it would resemble a dependent variable.

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Hi Guys,

I really need you help, I have to give in a lab report day after tomorrow. It is about the rate of reaction and the factors which affect the reaction. I did it at the beginning of the year and can't remember a thing from it. All I have are results, which are HCL concentrations over time, Does anyone have any idea how this could have been carried out? Thanks for your help in advance.

It's for a rate of reaction lab. Rates are defined by the change in concentration of the product or reactant per unit time...

You could actually have both as your variable. Change your concentration of HCl and then measure how much the concentration changes in the amount of time...

You can figure out how much your concentration changed with some stoichiometry by measuring the gas evolved or the mass change, I'm not seeing how color change could lead to her results...

Edit: After me and Keel talked this over some...is the graph a concentration vs time graph? Concentration of HCl at the x axis and time as the y axis? If so we both agree that you probably did color change because you likely measured the time it took for the reaction to go to completion...which you would only be able to measure with color change...

Keel Edit: or did you use pH and assume it represented the HCl conc?

Edited by Keel

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OK Guys, so what I managed to find out from some scraps of notes I have is that we used Na2S2O3 and HCl. I will post my results so that you can have a better look at the whole thing.

HCl concentration Time +/- 0.01s

high

57:00

53:51

45:54

medium

55:90

47:04

54:75

low

67:87

63:56

68:29

This is all I got.Please help... :(

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Yea. I'm going to say that you had 3 different concentrations of HCl as your independent variable and you timed how long it took for the reaction to go to completion which you likely measured using the color change method.

What you probably did was have equal volumes of your reactants but varying concentration of HCl. Under the beak was a piece of paper or something you could see underneath and during the reaction the solution was either turning dark or turning colorless. You simply timed how long it took for the paper to fully appear or completely be gone (covered up by the reaction getting darker).

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